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Saw Palmetto Benefits, Side Effects & Safety Information

Published: 13th May 2018. Last updated: 21th July 2019.

Shaun Ward MSc ANutr

Staff Writer


Saw palmetto is a supplement that is derived from the fruit of the serenoa repens palm tree, native to certain regions of North America such as Florida, Georgia, Cuba, and the Bahamas.

Due to its growth in this area, it was historically used by native Americans as a diuretic, sedative, aphrodisiac, and to help treat coughs.

More common uses of saw palmetto are to deal with issues with the prostate, urinary tract, and to enhance libido and hair growth.

The most popular form of saw palmetto is the oily extracts of the fatty portions of the dried berries.

It is not yet known what the active compounds are within the berries, although they likely exist in the “liposterolic” fraction of the fruit.

The Potential Benefits of Saw Palmetto

Below is a list of every potential benefit that's backed by credible scientific research:

It May Help With Hair Growth

Hair loss is a common condition that can be caused by a variety of factors, including genetics, certain medical conditions, hormonal changes, and the use of medications, such as stimulants and blood thinners.

Saw palmetto may help to prevent androgenic alopecia, which is a type of pattern baldness that can occur in both genders.

The mechanism to which it works is not known at this point, but it is hypothesized to block the enzyme that converts testosterone to DHT - an androgenic hormone believed to cause hair loss. Specifically, the n-hexane extract in saw palmetto may inhibit both isomers that produce the 5α-reductase enzyme [1].

At least in some lab studies saw palmetto has shown to impair the ability of ligands to bind to the α1-adrenergic receptor and thus inhibit any downstream signaling [2].

Further, it may also prevent the uptake of DHT in the hair follicles, and therefore reduce their ability to bind to hair receptors and have a negative effect [3].

A couple of relevant human trials also exist that can support the claims made by saw palmetto supplements.

200mg of saw palmetto, as part of a supplement mix with other ingredients, was able to reduce hair loss in 60% of men with androgenic alopecia [4].

A similar study also found that 320mg of saw palmetto taken for 2 years in men with male pattern baldness increased hair growth in ~30% of individuals. [5].

It May Help Issues With The Urinary Tract

Urinary tract symptoms are common among older men and can include issues like incontinence and difficulty urinating.

Saw palmetto may improve urinary symptoms associated with benign prostate hyperplasia — a condition that causes an enlargement of the prostate gland and results in decreased urine flow.

A supplement called Prostataplex containing a mix of herbal supplements including saw palmetto could reduce the symptoms associated with the urinary tract during benign prostate hyperplasia when taken for 3 months [8].

Similarly, another study found that consuming 320mg of saw palmetto by itself for 6 months reduced urinary tract issues, whilst improving urine flow and quality of life [9].

The mechanistic effects that saw palmetto has to provide this benefit is not well-established, but it is likely relevant to the suppression of α1-adrenergic signaling [10].

How To Take Saw Palmetto?

Interestingly, saw palmetto berries can be eaten whole or dried to incorporate within various teas. However, to supplement with saw palmetto then it needs to be purchased in liquid or tablet form after the fruit has been processed.

When taken as a dried supplement or a liquid extract, saw palmetto is most effective in the range of 160–320mg per day (assuming the supplement is 80-90% liposterolic compounds by weight) [11].

However, nearly all the studies on saw palmetto have been analyzing males, and so the recommended dosage for females is not known. It is advised that females look towards the lower end of this dosage range, whereas men can look towards the upper end of this range.

You should also consult with your doctor before taking saw palmetto to ensure your safety and appropriate dosage.

Saw Palmetto Safety And Side Effects

Studies and experts on herbal medicine suggest that saw palmetto supplements are generally safe for adults to take.

However, there are a few issues that people should be aware of before supplementing saw palmetto:

  • It is high in tannic acids, which bind to iron and reduce bioavailability [12].
  • Some minor side effects that have been reported are diarrhea, headaches, fatigue, nausea, vomiting, hot flushes, and vertigo.
  • Rare but serious side effects have been linked to saw palmetto including liver damage and pancreatitis – despite no clear causation being identified [13].


Saw palmetto is a supplement that is derived from the fruit of the serenoa repens palm tree, with active components in the “liposterolic” fraction of the fruit.

A good amount of evidence shows saw palmetto may be able to increase hair growth and help with issues of the urinary tract.

It can be viewed as a safe supplement, but high doses may inhibit iron absorption and lead to liver damage, diarrhea, headaches, and a few other notable side effects.

It is recommended to stay within the range of 160-320mg per day to avoid safety concerns and reap the potential benefits.

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